Art. Y. — Isotes on Malurus gouldii and Malurus cyaneus, 

 with special reference to changes in lolutnage. 



By ROBERT HALL. 



[Read 11th May, J899.] 



To identify the two species with which this paper deals, a key 

 is given by Dr. Sharpe in voL iv. of the Brit. Mus. Cat. Birds, 

 which, on carefully comparing with many specimens in my 

 cabinet, I find is particularly useful as regards the characters of 

 the blue coloring ; but the various measurements seem to differ 

 so much in some thirty skins I have handled, that the key to the 

 species seem to me to be the nature of the blue color of the male 

 bird. 



The British Museum keys are : — 



Malurus cyaneus^ Ellis. — Head, blue ; throat, blue-black ; 

 upper tail coverts black, smaller than M. gouldii; w-ing, 1-95"; 

 head, ear-coverts and mantle turquoise blue. 



Alalurus gouldii, Sharpe. — Head, blue ; no red on upper sur- 

 face ; throat, blue-black ; upper tail coverts, black ; larger than 

 cyaneus ; wing, 215"; head, ear-coverts and mantle rich cobalt- 

 blue ; mantle more extended than in M. cyimeus. 



Taking first the diti'erence in the length of wing \ cannot see 

 the charactei' is sufficiently strong as a leading one to constitute 

 a part of a basis for us to identify the species. Of mature l)irds 

 the wings measure : — 



M. cyaneus. 



a. - - - i-r. 



h. c. d - 1-95". 



e. f. • - T. 



S. - - - 2-2". 



Range from 1-9" to 22". 



M. gouldii. 

 a. Ik c. d - 2". 

 e. J.- - - 2-05". 

 g - - - 2-1". 

 li. - - - 2-15". 

 Range from 2" to 2 "IS". 



